The ATS-V is about a foot shorter and over 400 pounds lighter than the midsize CTS-V. The coupe is a few inches lower in height and comes with 18-inch wheels that are half an inch wider in the rear.

The ATS-V is about a foot shorter and over 400 pounds lighter than the midsize CTS-V. The coupe is a few inches lower in height and comes with 18-inch wheels that are half an inch wider in the rear. (Tom Snitzer / snitzerphotography.com)